The invention discloses a silicate electrode with a lead membrane as an intermediate layer and lead silicate as a sensitive membrane, and a preparation method thereof. According to the invention, a metal wire is used as a substrate and is electroplated with a layer of the lead membrane via an electrochemical process, and then the surface of the metal wire is coated with a layer of lead silicate insitu; since the layer of the lead membrane is additionally arranged between the metal wire and the lead silicate membrane, the bonding force of lead silicate is increased, and thus, the electrical impedance of the electrode is reduced; and after treatment at a certain constant temperature for a period of time, gaps among lead silicate particles are reduced, the response time of the electrode is shortened, and the sensitivity of the electrode is improved. The electrode provided by the invention has the advantages of high mechanical strength, small size, fast detection response, low impedance,good selectivity, long service life, etc.; and the electrode is cooperatively used with solid reference electrodes and applicable to on-line detection and long-term in-situ monitoring of the content of silicate ions in inland water bodies, cultivation water and chemical and chemical engineering aqueous mediums.